Contact bowl



June 5, 1923.

A.- 'WIGAND CONTACT BOWL Filedjune 5, 1922 Patented June 5, 1923.

' UNITED STATES PATENT orrica.

ALBERT WIGAND, OI HALLE, GERMANY, ASSIGNOR TO THE FIRE O1 CARL ms, 01'

' HALLE, GERMANY.

conrac'r sown.

To all'ichom it ma concern Be it known t at I, ALBERT 'WIGAND, a

citizen of the German Empire, residing at Halle, Germany, have invented a new and I useful Contact Bowl (for which I have filed an application in Germany December 13, 1918), of which the following is a speci-- fication.

The present invention relates to a con- 10 tact bowl, i. e. to a small spectacle glass which is destined to be laced directly upon the eyeball-so as to su ciently stick to the same in order to move along with the e e in viewing. By making such contact bow s, 18 as has hitherto taken place, of thin glass without working them later on, it is generally impossible to attain such a finish of the outer surface as is desirable. To improve the finish of the outer surface by 80 grinding is both diflicult and expensive;

moreover ground glass is not sufliciently resistive to the chemical action of the (alkaline) lachrymal fluid. Besides such a glam bowl is always easily liable to be smashed. as According to the invention a transparent, or anic substance, which is resistive to the lac rymal fluid as, e. g. cellon or celluloid, is softened by heating, having thereupon imparted to it by moulding or pressing the she. e of a bow having the size of the front ,sur ace of the eyeball and of about 1 mm thickness, and ultimately its front surfaceis brought to its suitably thickened middle part by means of grinding or polishing to the shape corresponding to the desired ens action. The front surface can also be particularly protected by a transparent lacquer coating.

Owing to the possibility of working the 40 front surface of the new contact bowl, an

optional form withinwide limits may be imarted to this surface. Hence a largenumr of such bowls ofuniform t ing the front surface, it is possible to attain in each separate bowl that'refractive, effect which is uisi-te for removing the existing defect o g the eye v(keratoconus, astigmatism of the cornea, myopia, hypermetropia, up cphccu).

7 made of the can be. manufaetured for stock and then, y finish- Application filed June c.1922. Serial No. 865,791.

The new contact bowl possesses a certain V Fig. 1 of the annexed drawings shows in a section on an enlarged scale an example o for manufacturing r stock the bowls which are to be finished later on according to the particular requirements; Fig. 2 shows in a section on the same scalean example for 7 manufacturing a dispersive, Fig. 3 an examIple for manufacturing a collective bowl.-

ig. 1 0, denotes a press-form and b a press-stamp. A layer 0 of cellon softened by heating is brought into the mould and then pressed against the latter so as to receive the form shown in Fig. 1., Fig. 2 shows a" dispersive glass which is lass shown in Flg. 1 by working the middT epart according to a spherical surface, the centre M of which is at a greater distance from the inner vertex of the bowlthan the centre M of the inner surface.- The original formis shown by dotted lines, the projecting margin has. been cut off. On its outside the bowl is provided with a l8ll1er coatin d. 1 Fig. 3 s ows a co ective bowl in which the centre M of the outer surface is nearer the vertex than the'centre M of the inner surface.

In the appended claim celluloid as well as bowls.

I claim: Contact bowl consisting of cellon and be g coated on its front surface with a transparent lacquer.

- ALBERT wleann. -Witn cellon are includedfor the above contact 

